Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: fossilshark on February 22, 2017, 12:11:52 pm
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my power transformer keeps blowing the fuse, there is a short between one of the b+ lines and ground even when the line is disconnected from the rest of the circuit. do i have a bad transformer? its an older transformer and the wires are kind of cracking
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It's entirely possible, if you are blowing fuses with nothing else connected past the fuse, then something in the PT sounds wrong. What do you mean by 'disconnected from the rest of the circuit? are both high voltage wires disconnected from the rectification and just loose? Have you made sure to put electric tape or something similar on the ends to ensure they're not touching at all? If so, then it's pretty likely the PT is bad, Seeing visible cracks is a pretty sure sign the wire cover has just gone out. You can either get it rewound or replace it.
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there is a short between one of the b+ lines and ground even when the line is disconnected from the rest of the circuit.
When you say short do you mean zero ohms? When you say "one of the B+ lines" do you mean one of the wires coming out of the transformer? If both answers are yes then the PT is probably bad. If you remove the bell cover from the PT you may be able to see a bare wire poking through the insulation. Sometimes this can be fixed with just some heat shrink tubing.